The present invention relates to a process for recovering copper values from ammoniacal leach liquors. There are many hydrometallurgical processes in which low levels of copper value are leached by ammoniacal leach liquors. One example of such a leaching process is the "cuprion" process disclosed in U.S. Pat. No. 3,983,017 to Lester Szabo entitled "Recovery of Metal Values from Manganese Deep Sea Nodules Using Ammoniacal Cuprous Leach Solutions," the teachings of which are incorporated herein by reference.
Another source of copper containing ammoniacal leach liquors is the pregnant liquor from certain in situ systems. An example of such an in situ system is disclosed in U.S. Pat. application Ser. No. 724,548, now U.S. Pat. No. 4,116,488, entitled "In Situ Mining Method and Apparatus," the teachings of which are incorporated herein by reference.
The recent discovery of a novel method of extracting molybdenum from dilute ammoniacal solutions is aided by the prior extraction of copper from such solutions. Thus, the present invention, in addition to extracting metallic copper from ammoniacal leach liquors as an end in itself, is useful in preparing ammoniacal leach liquors bearing both copper and molybdenum values for molybdenum extraction. For a more detailed discussion of molybdenum extraction from ammoniacal leach liquors see U.S. Pat. application Ser. No. 962,158 , entitled "Recovery of Molybdenum From Dilute Solutions," filed on even date herewith, the teachings of which are incorporated herein by reference.